Genetic testing to gain diagnostic clarity in neurofibromatosis type 2 and schwannomatosis.

Neurofibromatosis type 2 (NF2) and schwannomatosis (SWN) have distinct genetic etiologies but overlapping phenotypes. Genetic testing may be required for accurate diagnosis, which is critical for determining prognosis, screening recommendations, and treatment options. Our study aimed to compare the efficacy of germline-only versus paired (germline and tumor) genetic testing for clarifying the diagnosis in patients with features of NF2 and SWN. We performed a retrospective chart review of patients referred for NF2/SWN genetic testing at Massachusetts General Hospital from 2015 to 2020. Logistic regression analysis was performed to assess factors associated with diagnostic clarity. Overall, paired testing had 8.5 times greater odds of providing diagnostic clarity than germline-only testing (p < 0.01). Among patients who underwent paired testing, those who had analysis of two or more tumors had the greatest likelihood of gaining diagnostic clarity, with odds 13 times greater than patients who underwent germline-only testing (p < 0.01). Paired testing with analysis of one tumor significantly increased the odds of diagnostic clarity over germline-only testing by a factor of 6.5 (p < 0.01). These results have implications for genetic testing strategies and counseling patients about genetic testing utility. They also support the routine use of testing in individuals with suspected NF2 or SWN and improved insurance coverage for paired testing within this population.

Introduction to Cystic Fibrosis for Mental Health Care Coordinators and Providers: Collaborating to Promote Wellness.

To maximize health, individuals with cystic fibrosis (CF) follow a complex, burdensome daily care regimen. Managing CF is associated with a range of significant biopsychosocial challenges and places individuals with CF, and their caregivers, at greater risk for developing anxiety and depression. To promote wellness and address the potential barriers that affect management of this complex chronic illness, many individuals would benefit from treatment from a behavioral health provider. Social workers within multidisciplinary CF care teams are well positioned to respond to this need, and an expanding number of social workers serving as behavioral health providers in the community will be sought as a resource to provide treatment to this population. This article serves as a primer for social workers to maximize knowledge of the psychosocial and potential behavioral health needs of individuals with CF across the life span. To best support individuals with CF, authors describe the disease-specific manifestations and outline the numerous potential clinical targets for social work to promote wellness. The article concludes by highlighting the importance of communication with the medical team and considerations for effective collaborative care.

Recontact practices of cancer genetic counselors and an exploration of professional, legal, and ethical duty.

The duty to recontact continues to be revisited in the field of clinical genetics and is currently relevant for cancer genetic counseling given the transition from single-gene to multi-gene panel testing. We recruited cancer genetic counselors through the National Society of Genetic Counselors list-serv to complete an online survey assessing current practices and perspectives regarding recontacting patients about diagnostic genetic tests. Forty-one percent of respondents reported that they have recontacted patients to offer updated (new) diagnostic genetic testing (40/97). A majority (61%, 17/28), of genetic counselors who reported recontact specifically for panel testing indicated that the availability of management recommendations for genes not previously tested routinely was an important factor in the decision to recontact. All respondents who recontacted patients reported "improved patient care" as a perceived benefit. Respondents indicated that recontact is mostly a patient responsibility (49%), followed by a shared responsibility between the provider and patient (43%). Few respondents (2%) reported a uniform ethical duty to recontact patients regarding new and updated testing, while the majority (89%) felt that there was some degree of ethical duty. A greater percentage of those who reported past recontact practices reported intention to recontact in the future (p = 0.001). There is little consensus among the genetic counselor respondents about how to approach the recontacting of patients to offer updated genetic testing.

The role of viral introductions in sustaining community-based HIV epidemics in rural Uganda: evidence from spatial clustering, phylogenetics, and egocentric transmission models.

BACKGROUND: It is often assumed that local sexual networks play a dominant role in HIV spread in sub-Saharan Africa. The aim of this study was to determine the extent to which continued HIV transmission in rural communities--home to two-thirds of the African population--is driven by intra-community sexual networks versus viral introductions from outside of communities. METHODS AND FINDINGS: We analyzed the spatial dynamics of HIV transmission in rural Rakai District, Uganda, using data from a cohort of 14,594 individuals within 46 communities. We applied spatial clustering statistics, viral phylogenetics, and probabilistic transmission models to quantify the relative contribution of viral introductions into communities versus community- and household-based transmission to HIV incidence. Individuals living in households with HIV-incident (n = 189) or HIV-prevalent (n = 1,597) persons were 3.2 (95% CI: 2.7-3.7) times more likely to be HIV infected themselves compared to the population in general, but spatial clustering outside of households was relatively weak and was confined to distances <500 m. Phylogenetic analyses of gag and env genes suggest that chains of transmission frequently cross community boundaries. A total of 95 phylogenetic clusters were identified, of which 44% (42/95) were two individuals sharing a household. Among the remaining clusters, 72% (38/53) crossed community boundaries. Using the locations of self-reported sexual partners, we estimate that 39% (95% CI: 34%-42%) of new viral transmissions occur within stable household partnerships, and that among those infected by extra-household sexual partners, 62% (95% CI: 55%-70%) are infected by sexual partners from outside their community. These results rely on the representativeness of the sample and the quality of self-reported partnership data and may not reflect HIV transmission patterns outside of Rakai. CONCLUSIONS: Our findings suggest that HIV introductions into communities are common and account for a significant proportion of new HIV infections acquired outside of households in rural Uganda, though the extent to which this is true elsewhere in Africa remains unknown. Our results also suggest that HIV prevention efforts should be implemented at spatial scales broader than the community and should target key populations likely responsible for introductions into communities.

National integration of mental health screening and treatment into specialized care for cystic fibrosis: What predicts success?

OBJECTIVES: The CF Foundation sponsored competitive awards for Mental Health Coordinators (MHCs) from 2016 to 2018 to implement the international guidelines for mental health screening and treatment in US CF centers. Longitudinal surveys evaluated success in implementing these guidelines using the Consolidated Framework for Implementation Research (CFIR). METHODS: MHCs completed annual surveys assessing implementation from preparation/basic implementation (e.g., using recommended screeners) to full implementation/sustainability (e.g., providing evidence-based treatments). Points were assigned to questions through consensus, with higher scores assigned to more complex tasks. Linear regression and mixed effects models were used to: (1) examine differences in centers and MHC characteristics, (2) identify predictors of success, (3) model the longitudinal trajectory of implementation scores. RESULTS: A total of 122 MHCs (88.4% responded): Cohort 1, N = 80; Cohort 2, N = 30; and Cohort 3, N = 12. No differences in center characteristics were found. Significant improvements in implementation were observed across centers over time. Years of experience on a CF team was the only significant predictor of success; those with 1-5 years or longer reported the highest implementation scores. Change over time was predicted by >5 years of experience. CONCLUSIONS: Implementation of the mental health guidelines was highly successful over time. Funding for MHCs with dedicated time was critical. Longitudinal modeling indicated that CF centers with diverse characteristics could implement them, supported by evidence from the CF Patient Registry showing nearly universal uptake of mental health screening in the United States. Years of experience predicted better implementation, suggesting that education and training of MHCs and retention of experienced providers are critical to success.

Inhibition of LILRB2 by a Novel Blocking Antibody Designed to Reprogram Immunosuppressive Macrophages to Drive T-Cell Activation in Tumors.

Tumor-associated macrophages (TAM) play an important role in maintaining the immunosuppressive state of the tumor microenvironment (TME). High levels of CD163+ TAMs specifically are associated with poor prognosis in many solid tumor types. Targeting TAMs may represent a key approach in development of the next generation of cancer immune therapeutics. Members of the leukocyte immunoglobulin-like receptor B (LILRB) family, including LILRB2 (ILT4), are known to transmit inhibitory signals in macrophages and other myeloid cells. Leveraging bulk and single cell RNA-sequencing datasets, as well as extensive immunophenotyping of human tumors, we found that LILRB2 is highly expressed on CD163+ CD11b+ cells in the TME and that LILRB2 expression correlates with CD163 expression across many tumor types. To target LILRB2, we have developed JTX-8064, a highly potent and selective antagonistic mAb. JTX-8064 blocks LILRB2 binding to its cognate ligands, including classical and nonclassical MHC molecules. In vitro, JTX-8064 drives the polarization of human macrophages and dendritic cells toward an immunostimulatory phenotype. As a result, human macrophages treated with a LILRB2 blocker are reprogrammed to increase the activation of autologous T cells in co-culture systems. Furthermore, JTX-8064 significantly potentiates the activity of anti-PD-1 in allogeneic mixed lymphocyte reaction. In a human tumor explant culture, pharmacodynamic activity of JTX-8064 was observed in monotherapy and in combination with anti-PD-1. Collectively, our work provides strong translational and preclinical rationale to target LILRB2 in cancer.

Inactivation of LATS1/2 drives luminal-basal plasticity to initiate basal-like mammary carcinomas.

Basal-like breast cancers, an aggressive breast cancer subtype that has poor treatment options, are thought to arise from luminal mammary epithelial cells that undergo basal plasticity through poorly understood mechanisms. Using genetic mouse models and ex vivo primary organoid cultures, we show that conditional co-deletion of the LATS1 and LATS2 kinases, key effectors of Hippo pathway signaling, in mature mammary luminal epithelial cells promotes the development of Krt14 and Sox9-expressing basal-like carcinomas that metastasize over time. Genetic co-deletion experiments revealed that phenotypes resulting from the loss of LATS1/2 activity are dependent on the transcriptional regulators YAP/TAZ. Gene expression analyses of LATS1/2-deleted mammary epithelial cells notably revealed a transcriptional program that associates with human basal-like breast cancers. Our study demonstrates in vivo roles for the LATS1/2 kinases in mammary epithelial homeostasis and luminal-basal fate control and implicates signaling networks induced upon the loss of LATS1/2 activity in the development of basal-like breast cancer.

Differential expression of CCR8 in tumors versus normal tissue allows specific depletion of tumor-infiltrating T regulatory cells by GS-1811, a novel Fc-optimized anti-CCR8 antibody.

The presence of T regulatory (Treg) cells in the tumor microenvironment is associated with poor prognosis and resistance to therapies aimed at reactivating anti-tumor immune responses. Therefore, depletion of tumor-infiltrating Tregs is a potential approach to overcome resistance to immunotherapy. However, identifying Treg-specific targets to drive such selective depletion is challenging. CCR8 has recently emerged as one of these potential targets. Here, we describe GS-1811, a novel therapeutic monoclonal antibody that specifically binds to human CCR8 and is designed to selectively deplete tumor-infiltrating Tregs. We validate previous findings showing restricted expression of CCR8 on tumor Tregs, and precisely quantify CCR8 receptor densities on tumor and normal tissue T cell subsets, demonstrating a window for selective depletion of Tregs in the tumor. Importantly, we show that GS-1811 depleting activity is limited to cells expressing CCR8 at levels comparable to tumor-infiltrating Tregs. Targeting CCR8 in mouse tumor models results in robust anti-tumor efficacy, which is dependent on Treg depleting activity, and synergizes with PD-1 inhibition to promote anti-tumor responses in PD-1 resistant models. Our data support clinical development of GS-1811 to target CCR8 in cancer and drive tumor Treg depletion in order to promote anti-tumor immunity.

Status and advances in technologies for phosphorus species detection and characterization in natural environment- A comprehensive review.

Poor recovery of phosphorus (P) across natural environment (water, soil, sediment, and biological sources) is causing rapid depletion of phosphate rocks and continuous accumulation of P in natural waters, resulting in deteriorated water quality and aquatic lives. Accurate detection and characterization of various P species using suitable analytical methods provide a comprehensive understanding of the biogeochemical cycle of P and thus help its proper management in the environment. This paper aims to provide a comprehensive review of the analytical methods used for P speciation in natural environment by dividing them into five broad categories (i.e., chemical, biological, molecular, staining microscopy, and sensors) and highlighting the suitability (i.e., targeted species, sample matrix), detection limit, advantages-limitations, and reference studies of all methods under each category. This can be useful in designing studies involving P detection and characterization across environmental matrices by providing insights about a wide range of analytical methods based on the end user application needs of individual studies.

Impact of COVID-19 on mental health: Effects on screening, care delivery, and people with cystic fibrosis.

BACKGROUND: Depression and anxiety are two to four times more prevalent in people with CF (pwCF) than the general population. COVID-19 may exacerbate mental health challenges, increasing demand for psychological services, while decreasing their availability. We assessed the impact of the pandemic on depression and anxiety in pwCF, including how COVID-19 affected the frequency of mental health screening and the types of services provided. METHODS: A 38-item internet survey, completed in June 2020, assessed how COVID-19 affected: 1) the mental health clinician's role and screening processes; 2) barriers to screening and resource needs; 3) impact of COVID-19 on depression and anxiety, and 4) positive outcomes and confidence in sustaining mental health screening and treatment, including telehealth services, after the pandemic. RESULTS: Responses were obtained from 131 of the 289 US CF programs. Overall, 60% of programs (n=79) continued mental health screening and treatment, although less frequently; 50% provided individual tele-mental health interventions, and 9% provided telehealth group therapy. Clinically elevated depression symptoms (PHQ-9≥10; moderate to severe), were found in 12% of 785 pwCF, with 3.1% endorsing suicidal ideation. Similarly, elevated anxiety (moderate to severe; GAD-7≥10) was found in 13% of pwCF (n=779). CONCLUSIONS: The COVID-19 pandemic created an opportunity to implement innovative solutions to disruptions in mental health screening and treatment in CF programs. We found that pwCF had increased access to psychological interventions during the pandemic via telehealth, supporting the continued integration of tele-mental health screening and treatment into CF care.

Promoting emotional wellness in children with cystic fibrosis, Part I: Child and family resilience.

Attention should be given to individual and family well-being from a child's first interaction with the medical team and continuing throughout development, especially for families who experience chronic illnesses, such as cystic fibrosis (CF). While much attention has been given to the mental health of people with CF 12 years and older, this paper explores various areas for CF teams to assess and provide additional resources during the first 12 years of a child's life to promote child and family wellness. In this paper, we discuss parental mental health, social determinants of health, adherence/self-care, nutrition, attention to family lifestyle factors, engagement with school and peers, and modulator therapy for this age group of people with CF. This is the first of two companion papers which examines emotional wellness of children during the early years. The second paper examines mental health assessment and intervention for children under 12. Both encourage teams to strive to promote optimal child and family emotional health and wellness, emphasizing holistic health promotion and prevention, early identification, and intervention.

Promoting emotional wellness in children with CF, part II: Mental health assessment and intervention.

This is the second of two companion papers that examine the emotional wellness of children with cystic fibrosis (CF) during the early years of life, defined here as the period between birth and age 12. Both papers promote optimal mental health and well-being, with an emphasis on early identification and intervention. The first paper explores child and family resilience. Here, we discuss strategies for pediatric CF teams to provide routine, systematic mental health assessment, anticipatory guidance, brief intervention, and triage to evidence-based treatment when needed, while addressing barriers to accessing care. Many mental health conditions emerge before the age of 12, with the potential for lifelong effects on individuals, their families, and society. Living with a chronic illness such as CF can further increase the risk of mental health concerns and, in a bidirectional manner, their consequences for the quality of life, sustaining daily care, and health outcomes. There has been a significant focus in recent years on the mental health and wellness of adolescents and adults with CF, but less attention to specifics of depression and anxiety in younger children, or to other common pediatric comorbidities including trauma, developmental disorders such as attention-deficit/hyperactivity disorder or autism spectrum disorder, and oppositional behavior. Given the availability of psychometrically sound screening instruments and effective interventions, routinely addressing the mental health of children with CF and their families is feasible to integrate within multidisciplinary CF care, allowing for a personalized approach respecting individual needs, values, and goals.

Quantitative Method for Comparative Assessment of Particle Removal Efficiency of Fabric Masks as Alternatives to Standard Surgical Masks for PPE.

In response to the COVID-19 pandemic, cloth masks are being used to control the spread of virus, but the efficacy of these loose-fitting masks is not well known. Here, tools and methods typically used to assess tight-fitting respirators were modified to quantify the efficacy of community-produced and commercially produced fabric masks as personal protective equipment. Two particle counters concurrently sample ambient air and air inside the masks; mask performance is evaluated by mean particle removal efficiency and statistical variability when worn as designed and with a nylon overlayer, to independently assess fit and material. Worn as designed, both commercial surgical masks and cloth masks had widely varying effectiveness (53%-75% and 28%-91% particle removal efficiency, respectively). Most surgical-style masks improved with the nylon overlayer, indicating poor fit. This rapid testing method uses widely available hardware, requires only a few calculations from collected data, and provides both a holistic and aspect-wise evaluation of mask performance.

Development and Analytical Validation of a DNA Dual-Strand Approach for the US Food and Drug Administration-Approved Next-Generation Sequencing-Based Praxis Extended RAS Panel for Metastatic Colorectal Cancer Samples.

A next-generation sequencing method was developed that can distinguish single-stranded modifications from low-frequency somatic mutations present on both strands of DNA in formalin-fixed paraffin-embedded colorectal cancer samples. We applied this method for analytical validation of the Praxis Extended RAS Panel, a US Food and Drug Administration-approved companion diagnostic for panitumumab, on the Illumina MiSeqDx platform. With the use of the TruSeq amplicon workflow, both strands of DNA from the starting material were interrogated independently. Mutations were reported only if found on both strands; artifacts usually present on only one strand would not be reported. A total of 56 mutations were targeted within the KRAS and NRAS genes. A minimum read depth of 1800× per amplicon is required per sample but averaged >30,000× at maximum multiplexing levels. Analytical validation studies were performed to determine the simultaneous detection of mutations on both strands, reproducibility, assay detection level, precision of the assay across various factors, and the impact of interfering substances. In conclusion, this assay can clearly distinguish single-stranded artifacts from low-frequency mutations. Furthermore, the assay is accurate, precise, and reproducible, can achieve consistent detection of a mutation at 5% mutation frequency, exhibits minimal impact from tested interfering substances, and can simultaneously detect 56 mutations in a single run using 10 samples plus controls.

Field testing of lake water chemistry with a portable and an AUV-based mass spectrometer.

Two mass spectrometers (MS) are tested for the measurement of volatile substances, such as hydrocarbons and metabolic gases, in natural waters. KOALA is a backpackable MS operated from above the water surface, in which samples are pumped through a flow cell using a syringe. NEREUS is an underwater instrument hosted by an autonomous underwater vehicle (AUV) that is linked to a communications network to provide chemical data in real time. The mass analyzers of the two MS are nearly identical cycloids, and both use flat-plate membrane inlets. Testing took place in an eutrophic, thermally stratified lake exhibiting steep chemical gradients and significant levels of methane. KOALA provided rapid multispecies analysis of dissolved gases, with a detection limit for methane of 0.1 ppm (readily extendable to 0.01 ppm) and savings of time of at least a factor of 10 compared to that of conventional analysis. The AUV-mounted NEREUS additionally provided rapid spatial coverage and the capability of performing chemical surveys autonomously. Tests demonstrated the need for temperature control of a membrane inlet when steep thermal gradients are present in a water body, as well as the benefits of co-locating all sensors on the AUV to avoid interference from chemically different waters entering and draining from the free-flooding outer hull. The ability to measure dissolved volatiles provided by MS offers potential for complementarity with ionic sensors in the study of natural waters, such as in the case of the carbonate system.

A prospective randomized comparison of stranded vs. loose 125I seeds for prostate brachytherapy.

PURPOSE: To compare seed loss and dosimetric parameters between stranded and loose 125I seeds (LS) for prostate brachytherapy. METHODS AND MATERIALS: Sixty-four patients with 1997 American Joint Commission on Cancer (AJCC) clinical stage T1c or T2a prostate carcinoma were prospectively randomized to brachytherapy (144Gy) with RAPID Strand 125I seeds (RS) vs. LS (Oncura, Plymouth Meeting, PA) The treatment plan for each patient was devised before randomization, and was not modified based on the randomization. Each patient underwent magnetic resonance, computed tomography, and plain film radiographs on the day of the implant (Day 0) and 30 days later (Day 30). RESULTS: Overall, 21 of 62 patients (30%) experienced seed loss. Seed loss occurred in 15 of 32 of LS patients (47%) vs. 6 of 30 RS patients (23%; p=0.053). Mean seed loss was 1.09 in the LS patient vs. 0.43 in RS patients (p=0.062). Eight LS patients (25%) lost multiple seeds, compared to 3 stranded patients (10%). Despite the lesser degree of seed loss in patients who received stranded seeds, they had a paradoxical trend toward lower V100 and D90 values. CONCLUSION: This prospective randomized trial showed a strong trend toward a decrease in postimplant seed loss with stranded seeds. Improved seed retention may be more advantageous in a setting of less generous periprostatic coverage. The lowered risk seed migration seen with stranded seeds would presumably also decrease the likelihood of lung or cardiac seed embolization.

Statistical generation of training sets for measuring NO3(-), NH4(+) and major ions in natural waters using an ion selective electrode array.

Knowledge of ionic concentrations in natural waters is essential to understand watershed processes. Inorganic nitrogen, in the form of nitrate and ammonium ions, is a key nutrient as well as a participant in redox, acid-base, and photochemical processes of natural waters, leading to spatiotemporal patterns of ion concentrations at scales as small as meters or hours. Current options for measurement in situ are costly, relying primarily on instruments adapted from laboratory methods (e.g., colorimetric, UV absorption); free-standing and inexpensive ISE sensors for NO3(-) and NH4(+) could be attractive alternatives if interferences from other constituents were overcome. Multi-sensor arrays, coupled with appropriate non-linear signal processing, offer promise in this capacity but have not yet successfully achieved signal separation for NO3(-) and NH4(+)in situ at naturally occurring levels in unprocessed water samples. A novel signal processor, underpinned by an appropriate sensor array, is proposed that overcomes previous limitations by explicitly integrating basic chemical constraints (e.g., charge balance). This work further presents a rationalized process for the development of such in situ instrumentation for NO3(-) and NH4(+), including a statistical-modeling strategy for instrument design, training/calibration, and validation. Statistical analysis reveals that historical concentrations of major ionic constituents in natural waters across New England strongly covary and are multi-modal. This informs the design of a statistically appropriate training set, suggesting that the strong covariance of constituents across environmental samples can be exploited through appropriate signal processing mechanisms to further improve estimates of minor constituents. Two artificial neural network architectures, one expanded to incorporate knowledge of basic chemical constraints, were tested to process outputs of a multi-sensor array, trained using datasets of varying degrees of statistical representativeness to natural water samples. The accuracy of ANN results improves monotonically with the statistical representativeness of the training set (error decreases by ∼5×), while the expanded neural network architecture contributes a further factor of 2-3.5 decrease in error when trained with the most representative sample set. Results using the most statistically accurate set of training samples (which retain environmentally relevant ion concentrations but avoid the potential interference of humic acids) demonstrated accurate, unbiased quantification of nitrate and ammonium at natural environmental levels (±20% down to <10 µM), as well as the major ions Na(+), K(+), Ca(2+), Mg(2+), Cl(-), and SO4(2-), in unprocessed samples. These results show promise for the development of new in situ instrumentation for the support of scientific field work.

Effect of post-implant edema on prostate brachytherapy treatment margins.

PURPOSE: To determine if postimplant prostate brachytherapy treatment margins calculated on Day 0 differ substantially from those calculated on Day 30. METHODS: Thirty patients with 1997 American Joint Commission on Cancer clinical stage T1-T2 prostatic carcinoma underwent prostate brachytherapy with I-125 prescribed to 144 Gy. Treatment planning methods included using loose seeds in a modified peripheral loading pattern and treatment margins (TMs) of 5-8 mm. Postimplant plain radiographs, computed tomography scans, and magnetic resonance scans were obtained 1-4 hours after implantation (Day 0). A second set of imaging studies was obtained at 30 days after implantation (Day 30) and similarly analyzed. Treatment margins were measured as the radial distance in millimeters from the prostate edge to the 100% isodose line. The TMs were measured and tabulated at 90 degrees intervals around the prostate periphery at 0.6-cm intervals. Each direction was averaged to obtain the mean anterior, posterior, left, and right margins. RESULTS: The mean overall TM increased from 2.6 mm (+/-2.3) on Day 0 to 3.5 mm (+/-2.4) on Day 30. The mean anterior margin increased from 1.2 mm on Day 0 to 1.8 mm on Day 30. The posterior margin increased from 1.2 mm on Day 0 to 2.8 mm on Day 30. The lateral treatment margins increased most over time, with mean right treatment margin increasing from 3.9 mm on Day 0 to 4.7 mm on Day 30. CONCLUSION: Treatment margins appear to be durable in the postimplant period, with a clinically insignificant increase from Day 0 to Day 30.

Rectal fistulas after prostate brachytherapy.

PURPOSE: To compare the rectal and prostatic radiation doses for a prospective series of 503 patients, 44 of whom developed persistent rectal bleeding, and 2 of whom developed rectal-prostatic fistulas. METHODS AND MATERIALS: The 503 patients were randomized and treated by implantation with 125I vs. 103Pd alone (n = 290) or to 103Pd with 20 Gy vs. 44 Gy supplemental external beam radiotherapy (n = 213) and treated at the Puget Sound Veterans Affairs Medical Center (n = 227), Schiffler Cancer Center (n = 242) or University of Washington (n = 34). Patients were treated between September 1998 and October 2001 and had a minimum of 24 months of follow-up. The patient groups were treated concurrently. Treatment-related morbidity was monitored by mailed questionnaires, using standard American Urological Association and Radiation Therapy Oncology Group criteria, at 1, 3, 6, 12, 18, and 24 months. Patients who reported Grade 1 or greater Radiation Therapy Oncology Group rectal morbidity were interviewed by telephone to clarify details regarding their rectal bleeding. Those who reported persistent bleeding, lasting for >1 month were included as having Grade 2 toxicity. Three of the patients with rectal bleeding required a colostomy, two of whom developed a fistula. No patient was lost to follow-up. The rectal doses were defined as the rectal volume in cubic centimeters that received >50%, 100%, 200%, or 300% of the prescription dose. The rectum was considered as a solid structure defined by the outer wall, without attempting to differentiate the inner wall or contents. RESULTS: Persistent rectal bleeding occurred in 44 of the 502 patients, 32 of whom (73%) underwent confirmatory endoscopy. In univariate analysis, multiple parameters were associated with late rectal bleeding, including all rectal brachytherapy indexes. In multivariate analysis, however, only the rectal volume that received >100% of the dose was significantly predictive of bleeding. Rectal fistulas occurred in 2 patients (0.4%), both of whom had received moderate rectal radiation doses and extensive intervention for rectal bleeding. CONCLUSION: Partly on the basis of data from others and data presented here, we believe that the incidence of rectal fistulas can be much lower than in our series. High rectal radiation doses should be avoided a priori, to minimize the likelihood of rectal bleeding, and hence the likelihood that invasive procedures will be performed.

Perirectal seeds as a risk factor for prostate brachytherapy-related rectal bleeding.

PURPOSE: To correlate rectal wall doses and perirectal seed numbers with late rectal bleeding after prostate brachytherapy. METHODS AND MATERIALS: We studied 148 patients randomized to implantation with I-125 vs. Pd-103 at the VA Puget Sound HCS from 1998 through 2001 and for whom postimplant dosimetry was available. Implants were performed by standard techniques, using a modified peripheral loading pattern. A postimplant computed tomography (CT) scan (3 mm slice thickness) was obtained 1-4 h after implantation. Rectal doses were expressed as the R100, R200, and R300, defined as the rectal volume (cc) that received more than 100%, 200%, or 300% of the prescription dose, respectively. The rectum was considered to be a solid structure defined by the outer wall, without attempting to differentiate the inner wall or contents. In addition to conventional dose parameters, each patient's postimplant CT scan was reviewed for the number of seeds within 0, 0.1-2, and 2.1-4 mm of the outer rectal wall. The proximal edge of the seed was used for distance determinations from the outer rectal wall. Patients who reported Grade 1 or higher Radiation Therapy Oncology Group morbidity were contacted by telephone to obtain more details regarding their rectal bleeding. Those who reported persistent bleeding lasting for more than 1 month were categorized as Grade 2. RESULTS: Patients had a wide range of rectal wall doses, with R100 values ranging from 0.0 to 10.4 cc (median, 0.95 cc). Similarly, the number of perirectal seeds within 0.0 to 2.0 mm of the rectum varied widely, ranging from 0 to 12 seeds (median: 1 seed). Seven patients (7 of 144 = 5%) developed persistent rectal bleeding, one of whom required a colostomy. Both rectal radiation doses and the number of perirectal seeds were higher in patients with persistent rectal bleeding. The number of perirectal seeds < or =2.0 mm of the rectal wall was higher in patients with rectal bleeding (p = 0.037), but the number of seeds 2-4 mm from the wall were not related (p = 0.72). In multivariate regression analysis including prostatic D90 (the dose that covers 90% of the postimplant prostate), preimplant transrectal ultrasound volume, R300, and the number of seeds < or =2 mm from the rectal wall as independent variables, only the R300 was statistically significantly associated with the likelihood of persistent rectal bleeding (p = 0.025). CONCLUSION: A limited number of errant perirectal sources in itself does not appear to place patients at increased risk of rectal bleeding, providing that the overall rectal wall doses are within acceptable values.